Pond Algae

Microscopic algae, also called phytoplankton, are tiny, free-floating algae that give the pond water its characteristic green color. Microscopic algae are the primary producers of dissolved oxygen in pond water. The presence of a healthy level of microscopic algae in a pond is important for maintaining good water quality and health of the aquatic organisms in the pond, such as fish. Microscopic algae can undergo excessive blooms during mid-summer months, rising to the surface of the pond as a layer of yellow-green or reddish scum. A sudden die-off of microscopic algal blooms, caused by a change in water temperature or a stretch of several overcast days, can deplete dissolved oxygen levels in ponds to a critical level for the survival of aquatic organisms.

The clue for the pond owner in the control of microscopic algae is to look for a change in the color of the water that might signal that a bloom of microscopic algae is taking place. This color change would be from the clear green water of the healthy pond to a bright, pea-soup green